inhibitors of protein synthesis II Flashcards
prototype aminoglycoside
streptomycin
route of administration of streptomycin
IV; IM
List the aminoglycosides
- Streptomycin
- Gentamicin
- Tobramycin
- Amikacin
- Neomycin
route of administration of Gentamicin
- IV
- IM
- topical
route of administration of Tobramycin
- IV
- IM
- topical
route of administration of amikacin
- IV
- IM
route of administration of Neomycin
- oral
- topical
why is structure of aminoglycosides significant to their function
- aminoglycosides are polar and very large
- need to be actively transported (oxygen requiring process)
- under aerobic conditions, aminoglycoside are bactericidal
- NOT effective against anaerobic species
MOA of aminoglycoside
- irreversibly inhibit protein synthesis
- bind to 30S
- bactericidal
coverage of aminoglycoside
- aerobic G - enteric bacteria
- suspicion of sepsis or endocarditis
DOC for enterococcus species
aminoglycoside + penicillin
DOC tularemia (rabbit hunting disease)
Gentamicin
DOC pseudomonas aeruginosa
aminoglycoside + antipseud. pencillin
aminoglycosides are time or concentration dependent killers
concentration dependent killing
- increasing concentrations kill an increasing population os bacteria and at a more rapid rate
aminoglycoside have a significant post-antibiotic effect. What does this mean?
- antibacterial activity persists beyond the time that the abx is measurable
- single, large does has better efficacy than multiple smaller doses (reduces the toxic side effects)
aminoglycoside toxicity
- ototoxicity
- nephrotoxicity
why is it bad if a bacteria acquires resistance to one aminoglycoside
- cross resistance
- may exhibit cross resistance to the other aminoglycosides
are aminoglycosides mostly used alone to treat infections?
No, they are mostly used in combination with other abx
coverage of Chloramphenicol (chloromycetin)
broad spectrum antibiotic
- not first choice-reserved to life threatening infections
toxicity of Chloramphenicol (chloromycetin)
- dose-dependent
- fatal aplastic anemia
- bone marrow suppression
- “Gray baby” syndrome
MOA of Chloramphenicol (chloromycetin)
- reversibly binds the 50S subunit
- protein synthesis is inhibited
- bacteriostatic
adverse effect of MOA of Chloramphenicol (chloromycetin)
can inhibit mitochondrial protein synthesis in mammalian cells
route of administration of Chloramphenicol (chloromycetin)
Parenteral
distribution of Chloramphenicol (chloromycetin) in the body
- distributed widely in the body including eyes and CNS
- BEST CNS penetration
metabolism of Chloramphenicol (chloromycetin)
metabolized in the liver; conjugated with glucuronic acid
*has to be conjugated to be eliminated
“gray baby” syndrome is associated with Abx
Chloramphenicol (chloromycetin)
- inadequate activity of glucuronyl transferase in the newborn liver
- inability to conjugate the Abx
how do bacteria become resistant to Chloramphenicol (chloromycetin)
produce acetyl transferase which acetylates and inactivates Chloramphenicol
What are the three Tetracyclines
- Tetracycline
- Doxycycline
- Minocycline
what is the prototype tetracycline
tetracycline (Sumycin)
route of administration of tetracycline (sumycin)
- oral
- topical
route of administration of Doxycycline
oral
route of administration of minocycline
oral
MOA of tetracyclines
- inhibition of bacterial protein synthesis
- bacteriostatic
- bind reversibly to 30S ribosomes
coverage of tetracyclines
broad spectrum
DOC Cholera
Doxycycline
DOC Mycoplasma pneumonia
tetracyclines + erythromycin
DOC infections with chlamydia
tetracyclines + azithro/erythro
DOC Rickettsial infections
tetracyclines
Early, localized Borrelia Burgdorferi infection (lyme disease)
Doxycycline
DOC Vibrio species
tetracyclines
tetracycline chelate with what metals
- calcium
- iron (Fe2+)
- aluminum (Al3+)
deposition of tetracycline
deposit in bone and teeth (chelate Ca2+)
route of administration of tetracycline
oral is adequate but incomplete
adverse reactions of tetracyclines
- normal flora changes
- bone (inhibit bone elongation) and Teeth (dental discoloration)
- photosensitivity
who should not be given tetracyclines
- pregnant women
- can cross placenta and is excreted in breast milk
- children below the age of 8 years old
What is the only Glycylcycline
Tigecycline (tigacil)
MOA of Tigecycline
- binds to 30S
- bacteriostatic
coverage of Tigecycline
- similar to that of tetracycline, doxycycline, minocycline but shows activity against tetracycline-resistant organisms
what specific organisms does Tigecycline cover
- MRSA
- MRSE (staph epidermidis)
- PRSP (PCN-resistant strep pneumoniae)
- VRE (vancomycin-resistant enterococci)
what are the longer acting tetracyclines
- Doxycycline and Minocycline
- slowly excreted
- have longer plasma half-life and require less frequent administration